Fix Enum typing (#45)

* fix enum typing

* Improve typing

* _enum_value_cls_ typing

* add docs

* add typehints for try_value

Author: Luc1412

docs/changelog.rst

@@ -18,6 +18,7 @@ Bug Fixes
 ~~~~~~~~~
 - Fixed an issue that caused :class:`fortnite_api.Asset.resize` to raise :class:`TypeError` instead of :class:`ValueError` when the given size isn't a power of 2.
 - Fixed an issue that caused :class:`fortnite_api.ServiceUnavailable` to be raised with a static message as a fallback for all unhandled http status codes. Instead :class:`fortnite_api.HTTPException` is raised with the proper error message.
+- Fixed typing of our internal "Enum-like" classes. They are now typed as a :class:`py:enum.Enum`.
 
 Miscellaneous
 ~~~~~~~~~~~~~

fortnite_api/enums.py

@@ -27,7 +27,7 @@
 
 import types
 from collections.abc import Iterator, Mapping
-from typing import TYPE_CHECKING, Any, ClassVar, NamedTuple, TypeVar
+from typing import TYPE_CHECKING, Any, ClassVar, TypeVar
 
 from typing_extensions import Self
 
@@ -53,32 +53,51 @@
 
 
 def _create_value_cls(name: str, comparable: bool) -> type[NewValue]:
-    class _EnumValue(NamedTuple):
-        # Denotes an internal marker used to create the value class. The definition
-        # of this must be localized in this function because its methods
-        # are changed multiple times at runtime. This is exposed outside of this
-        # function as a type "NewValue", which denotes the type of the value class.
-        name: str
-        value: Any
-
-    cls = _EnumValue
-    cls.__name__ = '_EnumValue_' + name
-    cls.__repr__ = lambda self: f'<{name}.{self.name}: {self.value!r}>'
-    cls.__str__ = lambda self: f'{name}.{self.name}'
-    if comparable:
-        cls.__le__ = lambda self, other: isinstance(other, self.__class__) and self.value <= other.value
-        cls.__ge__ = lambda self, other: isinstance(other, self.__class__) and self.value >= other.value
-        cls.__lt__ = lambda self, other: isinstance(other, self.__class__) and self.value < other.value
-        cls.__gt__ = lambda self, other: isinstance(other, self.__class__) and self.value > other.value
-
-    return cls
+    # All the type ignores here are due to the type checker being unable to recognise
+    # Runtime type creation without exploding.
+
+    class EnumValue:
+        __slots__ = ("name", "value")
+
+        def __init__(self, name: str, value: EnumValue) -> None:
+            self.name: str = name
+            self.value: EnumValue = value
+
+        def __repr__(self) -> str:
+            return f'<{name}.{self.name}: {self.value!r}>'
+
+        def __str__(self) -> str:
+            return f'{name}.{self.name}'
+
+        if comparable:
+
+            def __le__(self, other: object) -> bool:
+                return isinstance(other, self.__class__) and self.value <= other.value
+
+            def __ge__(self, other: object) -> bool:
+                return isinstance(other, self.__class__) and self.value >= other.value
+
+            def __lt__(self, other: object) -> bool:
+                return isinstance(other, self.__class__) and self.value < other.value
+
+            def __gt__(self, other: object) -> bool:
+                return isinstance(other, self.__class__) and self.value > other.value
+
+    EnumValue.__name__ = '_EnumValue_' + name
+    return EnumValue
 
 
 def _is_descriptor(obj: type[object]) -> bool:
     return hasattr(obj, '__get__') or hasattr(obj, '__set__') or hasattr(obj, '__delete__')
 
 
 class EnumMeta(type):
+    if TYPE_CHECKING:
+        _enum_member_names_: ClassVar[list[str]]
+        _enum_member_map_: ClassVar[dict[str, NewValue]]
+        _enum_value_map_: ClassVar[dict[OldValue, NewValue]]
+        _enum_value_cls_: ClassVar[type[NewValue]]
+
     def __new__(
         cls,
         name: str,
@@ -124,29 +143,29 @@ def __new__(
         value_cls._actual_enum_cls_ = actual_cls
         return actual_cls
 
-    def __iter__(cls: type[Enum]) -> Iterator[Any]:
+    def __iter__(cls) -> Iterator[Any]:
         return (cls._enum_member_map_[name] for name in cls._enum_member_names_)
 
-    def __reversed__(cls: type[Enum]) -> Iterator[Any]:
+    def __reversed__(cls) -> Iterator[Any]:
         return (cls._enum_member_map_[name] for name in reversed(cls._enum_member_names_))
 
-    def __len__(cls: type[Enum]) -> int:
+    def __len__(cls) -> int:
         return len(cls._enum_member_names_)
 
     def __repr__(cls) -> str:
         return f'<enum {cls.__name__}>'
 
     @property
-    def __members__(cls: type[Enum]) -> Mapping[str, Any]:
+    def __members__(cls) -> Mapping[str, Any]:
         return types.MappingProxyType(cls._enum_member_map_)
 
-    def __call__(cls: type[Enum], value: str) -> Any:
+    def __call__(cls, value: str) -> Any:
         try:
             return cls._enum_value_map_[value]
         except (KeyError, TypeError):
-            raise ValueError(f"{value!r} is not a valid {cls.__name__}")
+            raise ValueError(f'{value!r} is not a valid {cls.__name__}')
 
-    def __getitem__(cls: type[Enum], key: str) -> Any:
+    def __getitem__(cls, key: str) -> Any:
         return cls._enum_member_map_[key]
 
     def __setattr__(cls, name: str, value: Any) -> None:
@@ -164,21 +183,17 @@ def __instancecheck__(self, instance: Any) -> bool:
             return False
 
 
-class Enum(metaclass=EnumMeta):
-    if TYPE_CHECKING:
-        # Set in the metaclass when __new__ is called. The newly
-        # created cls has these attributes set.
-        _enum_member_names_: ClassVar[list[str]]
-        _enum_member_map_: ClassVar[dict[str, NewValue]]
-        _enum_value_map_: ClassVar[dict[OldValue, NewValue]]
-        _enum_value_cls_: ClassVar[type[NewValue]]
+if TYPE_CHECKING:
+    from enum import Enum
+else:
 
-    @classmethod
-    def try_value(cls, value: Any) -> Any:
-        try:
-            return cls._enum_value_map_[value]
-        except (KeyError, TypeError):
-            return value
+    class Enum(metaclass=EnumMeta):
+        @classmethod
+        def try_value(cls, value: Any) -> Any:
+            try:
+                return cls._enum_value_map_[value]
+            except (KeyError, TypeError):
+                return value
 
 
 class KeyFormat(Enum):
@@ -580,9 +595,9 @@ def _from_str(cls: type[Self], string: str) -> Self:
 
 
 def create_unknown_value(cls: type[E], val: Any) -> NewValue:
-    value_cls = cls._enum_value_cls_
+    value_cls = cls._enum_value_cls_  # type: ignore # This is narrowed below
     name = f'UNKNOWN_{val}'
-    return value_cls(name=name, value=val)
+    return value_cls(name=name, value=val)  # type: ignore
 
 
 def try_enum(cls: type[E], val: Any) -> E:
@@ -591,6 +606,6 @@ def try_enum(cls: type[E], val: Any) -> E:
     If it fails it returns a proxy invalid value instead.
     """
     try:
-        return cls._enum_value_map_[val]
+        return cls._enum_value_map_[val]  # type: ignore # All errors are caught below
     except (KeyError, TypeError, AttributeError):
         return create_unknown_value(cls, val)

tests/test_enum.py

@@ -47,9 +47,9 @@ def test_dummy_enum():
 
     # Test immutability
     with pytest.raises(TypeError):
-        DummyEnum.FOO = "new"
+        DummyEnum.FOO = "new"  # type: ignore # This should raise an error
     with pytest.raises(TypeError):
-        del DummyEnum.FOO
+        del DummyEnum.FOO  # type: ignore  # This should raise an error
 
     # Test try_enum functionality
     valid_value = "foo"